A year after the BP oil spill and things are better along the Gulf Coast. Shrimpers are expecting a big harvest, tourists are returning, and fishermen are working again.
But grading the fate of wildlife that live in and around the Gulf of Mexico since that massive BP spill one year ago isn't so easy.
"I don't think anyone knows yet where we are," said Tom Brosnan, an environmental scientist at the National Oceanic and Atmospheric Administration, the government's lead agency in dealing with the spill. "We're doing variety of studies from deepwater habitats to the pelagic zone to the shoreline, and it's going to take some time to figure it out."
For starters, there are plenty of reasons for optimism. The surface waters have cleared and NOAA lifted closures that kept fishing boats out of the water for months last summer. Beaches considered by the agency to be "moderately or heavy oiled" have dropped to 66 miles this spring from 1,050 miles during the worst of the spill. Many marshes seem to be returning to productivity.
But beneath the waves, there are worrying signs.
Scientists are finding an alarming increase in dead or stranded baby bottlenosed dolphins, a trend that started before the April 20, 2010 blowout, but has increased since then. Ian MacDonald, a marine biologist at Florida State University, says the 160 or so dead dolphins are the tip of the biological iceberg.
"It represents a fraction of true mortality," MacDonald said. "If you wipe out a year class, the young of the year, you don't see that effect for several years."
Officials have also seen a rise in sea turtle deaths: 141 during the first few months of this year, which is above normal.
MacDonald noted that after the Exxon Valdez spill, the killer whale population in Prince William Sound dropped by 40 to 45 percent. However researchers were unable to prove that it was linked to the oil spill.
Something similar happened to the region's herring population, which took three years to crash after the Alaska spill and hasn't recovered yet.
Another ominous sign is less visible. Researchers using robot subs are finding oil coating fragile deepwater coral ecosystems. Samantha Joye, a University of Georgia researcher, found these dead patches of sea floor during five expeditions after the spill.
"The oil isn't gone; it's just not where we can see it," Joye told the Associated Press.
More than 60 federally-funded studies are underway this spring along the coast to determine what damages were done by the BP spill, and what could be the result of natural variability in animal populations.
NOAA has just started an aerial census of dolphins, turtles, whales and other marine mammals along the entire coast. Researchers are also beginning a more detailed comparison of two populations of dolphins, one in Barataria Bay, La., that was heavily impacted by oil, and another in Sarasota Bay, Fla., which was untouched. The animals are being caught, tagged and examined for a variety of health effects.
Some scientists have complained that the upcoming court battle between BP and the government over the spill has led research results to be locked up, at least for now. NOAA's Brosnan says he expects that will change once a final dollar figure is reached.
Critics like FSU's MacDonald, however, say the feds' Natural Resources Damage Assessment process "is not about truth; it's about money."
"The one lesson that should be ironclad coming out of this is that the people of this region depend on the health of their marine ecosystems," MacDonald said. "This was an event that hit home for us and we should carry that with us. And as we use oil, we should be willing to pay the real cost."
Despite the uncertainty about the long-term impacts of the BP spill, Washington is moving aggressively to return to business as usual. The Obama administration approved 10 exploratory permits in recent weeks, while Republicans in Congress are sponsoring bills to lift restrictions for drilling in new areas of the U.S. coast.
© 2012 Discovery Channel